Color filter and color display device using same

ABSTRACT

A color filter includes a substrate and a plurality of pixel units. The substrate defines a plurality of pixel areas. Each pixel area has a plurality of first sub-pixel areas, and each first sub-pixel area has a first area and a second area. The pixel units are formed on the substrate corresponding to the pixel areas. Each pixel unit is disposed in a corresponding pixel area and includes a plurality of color subtractive filter films and a plurality of color additive filter films. The color subtractive filter films are disposed in the first areas of the first sub-pixel areas of the corresponding pixel area, and the color additive filter films are disposed in the second areas of the first sub-pixel areas of the corresponding pixel area. A color display device with the color filter is also disclosed.

TECHNICAL FIELD

The present invention relates to color filters, and more particularly toa color filter suitable for use in a color display device.

BACKGROUND

With rapid development of technology, colorful and compact electronicproducts are becoming more and more popular to consumers. Colorreflective displays are used in various compact products due to itsexcellent characteristic of utilizing an incident light which isreflected as light sources to display images.

At present, a color filter is an important component of a colorreflective display for displaying color images. Referring to FIG. 1, aschematic view of a conventional color reflective display 100 is shown.The color reflective display 100 includes a color filter 102, a displaymedium layer 104 and an active element array substrate 106. The externallight L at an outside of the color reflective display 100 passes throughthe color filter 102 and the display medium layer 104 in sequence, thenis reflected back by the active element array substrate 106 to passthrough the display medium layer 104 and the color filter 102, andfinally enters into an user's eyes to obtain a colorful image. However,such configuration will decrease the overall light reflectivity and thelight penetration rate of the color reflective display 100, therebyaffecting the overall brightness of the color image.

Referring to FIG. 2, a plan view of a conventional color filter 200 isshown. The color filter 200 is mainly consisted of a substrate 202 and aplurality of pixel units 204 formed on the substrate 202. The pixelunits 204 include a red filter film R, a green filter film G and a bluefilter film B. In order to improve the light penetration rate of thecolor filter 200, the pixel units 204 further include a white filterfilm W, wherein the white filter film W can improve the brightness oflight passing through the color filter 200. However, using a whitefilter film W cannot obtain a satisfactory effect for improvement oflight brightness, and therefore this is not the efficient way to get ahigh light penetration rate.

SUMMARY

The present invention provides a color filter including a substrate anda plurality of pixel units. The substrate defines a plurality of pixelareas. The pixel units are formed on the substrate corresponding to thepixel areas. Each pixel unit is disposed in a corresponding pixel areaand includes a plurality of color subtractive filter films and a coloradditive filter film.

The present invention provides a color display device including anactive element array substrate, a color filter and a display mediumlayer disposed between the active element array substrate and the colorfilter. The color filter includes a substrate and a plurality of pixelunits. The substrate defines a plurality of pixel areas. The pixel unitsare formed on the substrate corresponding to the pixel areas. Each pixelunit is disposed in a corresponding pixel area and includes a pluralityof color subtractive filter films and a color additive filter film.

The present invention further provides a color filter including asubstrate and a plurality of pixel units. The substrate defines aplurality of pixel areas. Each pixel area has a plurality of firstsub-pixel areas, and each first sub-pixel area has a first area and asecond area. The pixel units are formed on the substrate correspondingto the pixel areas. Each pixel unit is disposed in a corresponding pixelarea and includes a plurality of color subtractive filter films and aplurality of color additive filter films. The color subtractive filterfilms are disposed in the first areas of the first sub-pixel areas ofthe corresponding pixel area, and the color additive filter films aredisposed in the second areas of the first sub-pixel areas of thecorresponding pixel area.

The present invention further provides a color display device includingan active element array substrate, a color filter and a display mediumlayer disposed between the active element array substrate and the colorfilter. The color filter includes a substrate and a plurality of pixelunits. The substrate defines a plurality of pixel areas. Each pixel areahas a plurality of first sub-pixel areas, and each first sub-pixel areahas a first area and a second area. The pixel units are formed on thesubstrate corresponding to the pixel areas. Each pixel unit is disposedin a corresponding pixel area and includes a plurality of colorsubtractive filter films and a plurality of color additive filter films.The color subtractive filter films are disposed in the first areas ofthe first sub-pixel areas of the corresponding pixel area, and the coloradditive filter films are disposed in the second areas of the firstsub-pixel areas of the corresponding pixel area.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more readily apparent to thoseordinarily skilled in the art after reviewing the following detaileddescription and accompanying drawings, in which:

FIG. 1 is a schematic view of a color reflective display according tothe related art.

FIG. 2 is a plan view of a color filter according to the related art.

FIG. 3 is a schematic view of a color display device according to afirst exemplary embodiment.

FIG. 4 is a schematic view of pixel units of a color filter of the colordisplay device of FIG. 3.

FIG. 5 is a schematic view of pixel units of a color filter according toa second exemplary embodiment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention will now be described more specifically withreference to the following embodiments. It is to be noted that thefollowing descriptions of preferred embodiments of this invention arepresented herein for purpose of illustration and description only. It isnot intended to be exhaustive or to be limited to the precise formdisclosed.

Referring to FIG. 3, a schematic view of a color display device 300,according to a first exemplary embodiment, is shown. The color displaydevice 300 includes an active element array substrate 302, a colorfilter 306 and a display medium layer 304. The color filter 306 isdisposed on the display medium layer 304. The display medium layer 304is disposed on the active element array substrate 302, and the displaymedium layer 304 is disposed between the active element array substrate302 and the color filter 306. In the present embodiment, the activeelement array substrate 302 is, for example, a thin film transistor(TFT) substrate. Furthermore, the display medium layer 304 can be,without limitation, a liquid crystal layer (LCL), an electro-phoreticlayer (EPL), an electro-wetting layer (EWL) or an organicelectro-luminescence layer (OELL).

Referring to FIG. 4, a schematic view of pixel units of the color filter306 is shown. The color filter 306 includes a substrate 308 and aplurality of pixel units 310 on the substrate 308. The substrate 308 hasa plurality of pixel areas 312 corresponding to the plurality of thepixel units 310. In FIG. 4, each pixel area 312 is substantiallyrectangular with a border thereof defined by dashed lines. Each pixelunit 310 is disposed in a corresponding one of the pixel areas 312 andincludes a plurality of color subtractive filter films 314 and a coloradditive filter film 316.

In detail, the color subtractive filter films 314 disposed in each pixelarea 312 may include a red filter film, a green filter film and a bluefilter film, and the color additive filter film 316 disposed in eachpixel area 312 can be selected from a magenta filter film, a cyan filterfilm or a yellow filter film. In a same pixel area 312, because thecolor additive filter film 316 is a mixture of two colors of the colorsubtractive filter films 314, the light penetration rate of the colorfilter 306 is effectively enhanced to improve the brightness and thesaturation of the displayed image.

In addition, in order to improve the light reflectivity and the lightpenetration rate of the color display device 300 and to augment thecolor gamut of the displayed image simultaneously, a color filterdescribed below can also be used in the color display device 300.

Referring to FIG. 5, a schematic view of pixel units of a color filter406, according to a second embodiment, is shown. The color filter 406includes a substrate 408 and a plurality of pixel units 410 on thesubstrate 408. The substrate 408 defines a plurality of pixel areas 412corresponding to the pixel units 410. Each pixel area 412 is furtherdivided into a plurality of first sub-pixel areas 414. In the presentembodiment, the shape of the first sub-pixel area 414 is square. Inother embodiments, the shape of the first sub-pixel area 414 can be,without limitation, regularly polygonal, circular or irregularlypolygonal. The first sub-pixel areas 414 each include a first area 414 aand a second area 414 b. In the present embodiment, the size of thefirst area 414 a is equal to that of the second area 414 b. In otherembodiments, the size of the first area 414 a can be larger than that ofthe second area 414 b.

Each pixel unit 410 is disposed in a corresponding pixel area 412 andincludes a plurality of color subtractive filter films 418 and aplurality of color additive filter films 420. The plurality of colorsubtractive filter films 418 may include a red filter film R, a greenfilter film G and a blue filter film B, while the plurality of coloradditive filter films 420 may include a magenta filter film M, a cyanfilter film C and a yellow filter film Y. Meanwhile, the plurality ofcolor subtractive filter films 418 are each disposed in a correspondingfirst area 414 a of the first sub-pixel area 414, and the plurality ofcolor additive filter films 420 are each disposed in a correspondingsecond area 414 b of the first sub-pixel area 414.

In the present embodiment, the color subtractive filter film 418 and thecolor additive filter film 420 are respectively disposed in the firstarea 414 a and the second area 414 b of the first sub-pixel area 414.Specifically, the red filter film R and the yellow filter film Y arerespectively disposed in the first area 414 a and the second area 414 bof one first sub-pixel area 414, thereby causing the lights passingthrough the red filter film R and the yellow filter film Y to mix andform an orange light. The color gamut of the orange light is determinedby the area ratio of the red filter film R relative to the yellow filterfilm Y.

Simultaneously, the green filter film G and the cyan filter film C arerespectively disposed in the first area 414 a and the second area 414 bof another first sub-pixel area 414. Thus, the lights passing throughthe green filter film G and the cyan filter film C are mixed and form alame light. At the same time, the blue filter film B and the magentafilter film M are respectively disposed in the first area 414 a and thesecond area 414 b of a further first sub-pixel area 414, thereby causingthe lights passing through the blue filter film B and the magenta filterfilm M to mix and form a purple light. The color gamut of the lame lightis determined by the area ratio of the green filter film G relative tothe cyan filter film C, while the color gamut of the purple light isdetermined by the area ratio of the blue filter film B relative to themagenta filter film M. Thus, the color gamut of the light after passingthrough the color filter 406 is determined by the area ratio of thefirst area 414 a relative to the second area 414 b.

In addition, in the present embodiment, each pixel area 412 can furtherinclude a second sub-pixel area 416, and the pixel unit 410 can furtherinclude a white filter film 422 disposed in the second sub-pixel area416 to increase an intensity of the light passing through the colorfilter 406.

To sum up, in the above-illustrated color filters, the color subtractivefilter film and the color additive filter film are disposed in a singlepixel area, thereby not only increasing the light intensity of the colorfilter, but also maintaining the color gamut of the light passingthrough the color filter. In other words, such configuration of thecolor filter not only can improve the brightness of the color displaydevice, but also can maintain the color gamut of the displayed images.

While the invention has been described in terms of what is presentlyconsidered to be the most practical and preferred embodiments, it is tobe understood that the invention needs not be limited to the disclosedembodiment. On the contrary, it is intended to cover variousmodifications and similar arrangements included within the spirit andscope of the appended claims which are to be accorded with the broadestinterpretation so as to encompass all such modifications and similarstructures.

What is claimed is:
 1. A color filter comprising: a substrate defining aplurality of pixel areas, each pixel area having a plurality of firstsub-pixel areas, each first sub-pixel area having a first color area anda second color area, wherein said second color area is adjacent to anddirectly connected to the first color area, the first color area and thesecond color area being not overlapped with each other, and the firstsub-pixel areas being not connected to each other; and a plurality ofpixel units formed on the substrate corresponding to the pixel areas,each pixel unit disposed in a corresponding pixel area and comprising aplurality of color subtractive filter films and a plurality of coloradditive filter films, wherein the color subtractive filter films aredisposed in said first color areas of corresponding said first sub pixelarea, the color additive filter films are disposed in said second colorareas of corresponding said first sub pixel area, the color subtractivefilter films comprise a red filter film, a green filter film and a bluefilter film, and the color additive filter films comprise a magentafilter film, a cyan filter film and a yellow filter film.
 2. The colorfilter according to claim 1, wherein the size of said first color areais not less than that of said second color area.
 3. The color filteraccording to claim 1, wherein each pixel area further has a secondsub-pixel unit further comprises a white filter film disposed in thesecond sub-pixel area.
 4. The color filter according to claim 1, whereina shape of the first sub-pixel area is selected from one of regularlypolygonal, circular and irregularly polygonal.
 5. The color filteraccording to claim 1, wherein the color subtractive filter filmscomprise a red filter film, a green filter film and a blue filter film,the color additive filter films comprise a magenta filter film, a cyanfilter film and a yellow filter film, the red filter film and the yellowfilter film are respectively disposed in the first color area and thesecond color area of one of the first sub-pixel areas, the green filterfilm and the cyan filter film are respectively disposed in the firstcolor area and the second color area of another one of the firstsub-pixel areas, and the blue filter film and the magenta filter filmare respectively disposed in the first color area and the second colorarea of another one of the first sub-pixel areas.
 6. The color filteraccording to claim 1, wherein the size of said first color area islarger than said second color area.
 7. A color display devicecomprising: an active element array substrate; a color filtercomprising: a substrate defining a plurality of pixel areas, each pixelarea having a plurality of first sub-pixel areas, each first sub-pixelarea having a first color area and a second color area, wherein saidsecond color area is adjacent to and directly connected to the firstcolor area, the first color area and the second color area being notoverlapped with each other, and the first sub-pixel areas being notconnected to each other; and a plurality of pixel units formed on thesubstrate corresponding to the pixel areas, each pixel unit disposed ina corresponding pixel area and comprising a plurality of colorsubtractive filter films and a plurality of color additive filter films,wherein the color subtractive filter films are disposed in said firstcolor areas of corresponding said first sub pixel area, the coloradditive filter films are disposed in said second color areas ofcorresponding said first sub pixel area, the color subtractive filterfilms comprise a red filter film, a green filter film and a blue filterfilm, and the color additive filter films comprise a magenta filterfilm, a cyan filter film and a yellow filter film; and a display mediumlayer disposed between the active element array substrate and the colorfilter.
 8. The color display device according to claim 7, wherein thesize of said first color area is not less than that of said second colorarea.
 9. The color display device according to claim 7, wherein eachpixel area further has a second sub-pixel area, and each pixel unitfurther comprises a white filter film disposed in the second sub-pixelarea.
 10. The color display device according to claim 7, wherein a shapeof the first sub-pixel area is selected from one of regularly polygonal,circular and irregularly polygonal.
 11. The color display deviceaccording to claim 7, wherein the color subtractive filter filmscomprise a red filter film, a green filter film and a blue filter film,the color additive filter films comprise a magenta filter film, a cyanfilter film and a yellow filter film, the red filter film and the yellowfilter film are respectively disposed in the first color area and thesecond color area of one of the first sub-pixel areas, the green filterfilm and the cyan filter film are respectively disposed in the firstcolor area and the second color area of another one of the firstsub-pixel areas, and the blue filter film and the magenta filter filmare respectively disposed in the first color area and the second colorarea of another one of the first sub-pixel areas.
 12. The color filteraccording to claim 7, wherein the size of said first area is larger saidsecond area.